Vehicles and methods for controlling internal combustion engine rotational speeds

Abstract

Vehicles and methods for controlling internal combustion engine rotational speeds are disclosed. Vehicles described herein include an internal combustion engine having a crankshaft and a plurality of drive wheels mechanically coupled to the crankshaft of the internal combustion engine. Embodiments described herein determine a target wheel torque, determine a base increase rate of engine rotational speed, increase an engine rotational speed of the internal combustion engine based on the base increase rate of engine rotational speed, determine an estimated wheel torque, determine an updated increase rate of engine rotational speed based on the target wheel torque and the estimated wheel torque, and increase the engine rotational speed of the internal combustion engine based on the updated increase rate of engine rotational speed.

What is claimed is: 
     
         1 . A vehicle comprising:
 one or more processors;   one or more memory modules communicatively coupled to the one or more processors;   an internal combustion engine comprising a crankshaft, wherein the internal combustion engine is communicatively coupled to the one or more processors;   a plurality of drive wheels mechanically coupled to the crankshaft of the internal combustion engine; and   machine readable instructions stored in the one or more memory modules that cause the vehicle to perform at least the following when executed by the one or more processors:
 determine a target wheel torque; 
 determine a base increase rate of engine rotational speed; 
 increase an engine rotational speed of the internal combustion engine based on the base increase rate of engine rotational speed; 
 determine an estimated wheel torque; 
 determine an updated increase rate of engine rotational speed based on the target wheel torque and the estimated wheel torque; and 
 increase the engine rotational speed of the internal combustion engine based on the updated increase rate of engine rotational speed. 
   
     
     
         2 . The vehicle of  claim 1 , wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine a requested acceleration amount;   determine a vehicle speed; and   determine the target wheel torque based on the requested acceleration amount and the vehicle speed.   
     
     
         3 . The vehicle of  claim 2 , wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine a target acceleration profile based on the requested acceleration amount and the vehicle speed; and   determine the target wheel torque based on the target acceleration profile.   
     
     
         4 . The vehicle of  claim 2 , further comprising:
 an accelerator pedal position sensor communicatively coupled to the one or more processors and outputting an accelerator pedal position signal (P accel ) indicative of a position of an accelerator pedal;   wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine the requested acceleration amount based on the accelerator pedal position signal (P accel ). 
   
     
     
         5 . The vehicle of  claim 1 , further comprising:
 at least one wheel speed sensor communicatively coupled to the one or more processors and outputting a wheel speed signal indicative of a speed of at least one of the plurality of drive wheels;   wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine the estimated wheel torque based on the wheel speed signal. 
   
     
     
         6 . The vehicle of  claim 1 , wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine the updated increase rate of engine rotational speed to be greater than the base increase rate of engine rotational speed when the estimated wheel torque is greater than the target wheel torque.   
     
     
         7 . The vehicle of  claim 1 , wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine the updated increase rate of engine rotational speed to be less than the base increase rate of engine rotational speed when the estimated wheel torque is less than the target wheel torque.   
     
     
         8 . The vehicle of  claim 1 , wherein the machine readable instructions, when executed by the one or more processors, cause the vehicle to:
 determine a difference between the target wheel torque and the estimated wheel torque; and   determine the updated increase rate of target engine rotational speed based on the difference.   
     
     
         9 . A hybrid vehicle comprising:
 one or more processors;   one or more memory modules communicatively coupled to the one or more processors;   a mechanical power distribution apparatus comprising a sun gear, a plurality of planetary gears, a carrier, and a ring gear, wherein the plurality of planetary gears mesh with the ring gear and the sun gear, wherein the plurality of planetary gears are mechanically coupled to the carrier;   an internal combustion engine comprising a crankshaft, wherein the crankshaft is mechanically coupled to the carrier of the mechanical power distribution apparatus;   a plurality of drive wheels;   a first motor-generator comprising an output shaft, wherein the output shaft of the first motor-generator is mechanically coupled to the sun gear;   a second motor-generator comprising an output shaft, wherein the output shaft of the second motor-generator is mechanically coupled to the plurality of drive wheels and is mechanically coupled to the ring gear;   an electrical energy storage device electrically coupled to the first motor-generator and the second motor-generator such that the electrical energy storage device can provide electrical energy to the first motor-generator and the second motor-generator; and   machine readable instructions stored in the one or more memory modules that cause the hybrid vehicle to perform at least the following when executed by the one or more processors:
 determine a target wheel torque; 
 determine a base increase rate of engine rotational speed; 
 increase an engine rotational speed of the internal combustion engine by controlling an amount of electrical energy provided from the electrical energy storage device to the first motor-generator based on the base increase rate of engine rotational speed; 
 determine an estimated wheel torque; 
 determine an updated increase rate of engine rotational speed based on the target wheel torque and the estimated wheel torque; and 
 increase the engine rotational speed of the internal combustion engine by controlling the amount of electrical energy provided from the electrical energy storage device to the first motor-generator based on the updated increase rate of engine rotational speed. 
   
     
     
         10 . The hybrid vehicle of  claim 9 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine a requested acceleration amount;   determine a vehicle speed; and   determine the target wheel torque based on the requested acceleration amount and the vehicle speed.   
     
     
         11 . The hybrid vehicle of  claim 10 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine a target acceleration profile based on the requested acceleration amount and the vehicle speed; and   determine the target wheel torque based on the target acceleration profile.   
     
     
         12 . The hybrid vehicle of  claim 9 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine the updated increase rate of engine rotational speed to be greater than the base increase rate of engine rotational speed when the estimated wheel torque is greater than the target wheel torque.   
     
     
         13 . The hybrid vehicle of  claim 9 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine the updated increase rate of engine rotational speed to be less than the base increase rate of engine rotational speed when the estimated wheel torque is less than the target wheel torque.   
     
     
         14 . The hybrid vehicle of  claim 9 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine a difference between the target wheel torque and the estimated wheel torque; and   determine the updated increase rate of target engine rotational speed based on the difference.   
     
     
         15 . The hybrid vehicle of  claim 9 , further comprising:
 a first current sensor for sensing a first amount of current provided to the first motor-generator; and   a second current sensor for sensing a second amount of current provided to the second motor-generator;   wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine an estimated output torque of the first motor-generator based on the sensed first amount of current; 
 determine a first amount of estimated torque transferred to the plurality of drive wheels based on the estimated output torque of the first motor-generator; 
 determine an estimated output torque of the second motor-generator based on the sensed second amount of current; and 
 determine the estimated wheel torque to be a sum of the first amount of estimated torque transferred to the plurality of drive wheels and the estimated output torque of the second motor-generator. 
   
     
     
         16 . The hybrid vehicle of  claim 15 , wherein the machine readable instructions, when executed by the one or more processors, cause the hybrid vehicle to:
 determine the first amount of estimated torque transferred to the plurality of drive wheels based on a gear ratio of the mechanical power distribution apparatus.   
     
     
         17 . A method for controlling an engine rotational speed of an internal combustion engine, the method comprising:
 determining a target wheel torque;   determining a base increase rate of engine rotational speed;   increasing the engine rotational speed of the internal combustion engine based on the base increase rate of engine rotational speed;   determining an estimated wheel torque;   determining an updated increase rate of engine rotational speed based on the target wheel torque and the estimated wheel torque; and   increasing the engine rotational speed of the internal combustion engine based on the updated increase rate of engine rotational speed.   
     
     
         18 . The method of  claim 17 , further comprising:
 determining a requested acceleration amount;   determining a vehicle speed; and   determining the target wheel torque based on the requested acceleration amount and the vehicle speed.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining a target acceleration profile based on the requested acceleration amount and the vehicle speed; and   determining the target wheel torque based on the target acceleration profile.   
     
     
         20 . The method of  claim 17 , further comprising:
 determining the updated increase rate of engine rotational speed to be greater than the base increase rate of engine rotational speed when the estimated wheel torque is greater than the target wheel torque; and   determining the updated increase rate of engine rotational speed to be less than the base increase rate of engine rotational speed when the estimated wheel torque is less than the target wheel torque.